From: Mattias Jonsson
Date: January 22 2011 6:09pm
Subject: Re: bzr commit into mysql-5.5 branch (jorgen.loland:3256) Bug#55385
Bug#57373
List-Archive: http://lists.mysql.com/commits/129378
Message-Id: <4D3B1D4C.4010700@oracle.com>
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Hi Jorgen,
Sorry for taking so long time.
After looking into it from the storage engine's view I agree with
Matthias Leich comment [5 Jan 21:20] that MyISAM is not rolled back is
an acceptable behavior (since it is not transactional). But the error
code is bad, since it is a very general storage engine error. It would
be better if it was the same as for InnoDB.
My suggestion would be to simply translate the given handler error to a
server error like other error codes are handled in handler::print_error.
The error is originally from the MyISAM engine/handler and is returned
through the partitioning handler).
Which would give the following patch:
=== modified file 'sql/handler.cc'
--- sql/handler.cc 2011-01-11 11:09:54 +0000
+++ sql/handler.cc 2011-01-22 17:41:21 +0000
@@ -2657,6 +2657,7 @@
break;
case HA_ERR_KEY_NOT_FOUND:
case HA_ERR_NO_ACTIVE_RECORD:
+ case HA_ERR_RECORD_DELETED:
case HA_ERR_END_OF_FILE:
textno=ER_KEY_NOT_FOUND;
break;
And the error/warnings returned will then be:
mysqltest: At line 11: query 'UPDATE t1 AS A NATURAL JOIN t1 B SET A.a =
2, B.b = 3' failed: 1032: Can't find record in 't1'
Warnings from just before the error:
Error 1032 Can't find record in 't1'
Error 1105 An error occured in multi-table update
For both MyISAM and InnoDB.
I think this is an acceptable behavior for this 'almost meaningless and
theoretic interest only' query ;)
I.e give the error "Can't find record in 't1'" and if one checks the
warnings like 'SHOW WARNINGS' one will also get "An error occured in
multi-table update"
To complete my proposed change, a test case with both MyISAM and InnoDB
would be good.
Please feel free to reassign to me...
Regarding fixing unnecessary work I think in this case it is not needed,
since it is a 'bad' query anyway, and I think that there might be
working queries that changes the PK/partitioning columns so that the
records stay within the same partitions.
Regards
Mattias
On 2011-01-17 10.26, Jorgen Loland wrote:
> #At file:///export/home/jl208045/mysql/mysql-5.5/ based on revid:john.embretsen@stripped
>
> 3256 Jorgen Loland 2011-01-17
> Bug#55385: UPDATE statement throws an error, but still updates the
> table entries
> Bug#57373: Multi update+InnoDB reports ER_KEY_NOT_FOUND if a table
> is updated twice
>
> Partitioning fails if multi-update updates the same partitioned
> table twice and the partitioning key is updated. This is
> because updates on the first table may move records from one
> partition to another, and update on the second table will fail
> to locate the records to update due to this.
>
> In InnoDB (BUG#57373), the result was that updates on the
> first table were performed. The transaction was then aborted
> once updates on the second table failed to locate records.
> Error ER_KEY_NOT_FOUND was returned. Problem: unneccessary work
> was performed (update + abort) and misleading error message
> returned.
>
> In MyISAM (BUG#55385), the result was that updates on the first
> table were performed. The transaction was then stopped once
> updates on the second table failed to locate records. Error
> "Got error 134 from storage engine" was returned. However,
> since MyISAM is unable to abort, the updates on the first
> table were still in effect. Problem: misleading error message
> and half-performed transaction.
>
> The fix is to chech if multi-table update will
> a) update the same partition twice, and
> b) at least one of these will update the partitioning key
> and thereby risk moving records to another partition.
> If this is the case, a meaningful error message is issued
> before any update work has been done.
> @ mysql-test/r/partition.result
> Add test for bugs 55385 and 57373.
> @ mysql-test/t/partition.test
> Add test for bugs 55385 and 57373.
> @ sql/share/errmsg-utf8.txt
> New error message for multi-table update where the same partition is updated twice.
> @ sql/sql_update.cc
> Check if multi-table update is about to update the same partitioned table twice and issue error.
>
> modified:
> mysql-test/r/partition.result
> mysql-test/t/partition.test
> sql/share/errmsg-utf8.txt
> sql/sql_update.cc
[snip...]